Mobile telephones, personal digital assistants, and similar portable electronic devices that have telecommunications capabilities may be equipped with a push-to-talk feature that allows a user of the device to simultaneously speak to one or more users of similarly equipped devices by pushing a single button on the device. That is, when a first user in a push-to-talk group presses a push-to-talk button on a device and speaks into the device, the voice of the first user may be heard on the devices of the other users in the group. The other users cannot transmit from their devices in a push-to-talk manner as long as the first user keeps the push-to-talk button on the first user's device depressed. When the first user releases the push-to-talk button, a second user in the group may then press the push-to-talk button on the second user's device and communicate with the other members of the group in a similar manner. In this way, communication can occur between the members of a group without the need for setting up a conference call among the members. Such half-duplex communication can also prevent the members of the group from attempting to speak simultaneously and can prevent background noise that may be occurring in the vicinity of one of the group members from being overheard by the other members, as may be the case in a conference call.
Some devices may also be equipped with an active noise cancelation feature and/or an active noise reduction feature. As used herein, active noise cancelation may refer to the attenuation of background noise in sounds received by a device, and active noise reduction may refer to the attenuation of background noise in sounds transmitted by a device. In some cases, active noise cancelation and/or active noise reduction may be achieved through the use of a plurality of microphones on a headset that is coupled to a telecommunications device. At least one of the microphones may be configured such that the voice of the user of the device is the primary component of the sound received by the microphone. The other microphones on the headset may be configured such that background noise in the user's vicinity is the primary component of the sound received by the microphones. An electrical signal generated by the background noise-focused microphones may be analyzed and an electrical signal that is the inverse of the background noise signal may then be generated. For active noise cancelation, the inverse signal may be added to the background noise signal and an incoming sound-based signal, such as the other party in a telephone call or a music recording. In this way, the device user may experience an attenuation of ambient background noise and may hear the incoming sounds more clearly. For active noise reduction, the inverse signal may be added to the background noise signal and the signal generated by the voice-focused microphone when the device user is on a telephone call. In this way, the other party in the telephone call may experience an attenuation of the background noise in the device user's vicinity and may hear the device user's voice more clearly.
Any component with a capability for telecommunication may be referred to herein as a handset, a device, a telecommunications device, or a mobile device, but it should be understood that such a component is not necessarily transportable. Also, it should be understood that the devices described herein do not necessarily have push-to-talk capabilities, active noise cancelation capabilities, or active noise reduction capabilities.